BESTSELLER O2 clean 12L Eurocylinder Twinset with Flat Bottom (Concave), high-quality BtS stainless steel twinning bands, and manifold with an isolator.

These flat-bottom manifolded doubles are our best sellers. With a working pressure of 232 bar, the twinset stands independently, thanks to a concave bottom. They are assembled with robust 2-inch wide marine-grade stainless steel BtS twinning bands featuring Delrin thumbwheels. The dependable barrel-type reliable BtS manifold and valves complement the sets.

All our twinsets come with O2 clean VIP stickers and decals as of the month of purchase. All sets are tested to working pressure and depressurised before shipping by courier allowing you to adjust the centre manifold before your first fill.

UK Delivery Options

Because Twinsets are heavy, oversized and fragile, they can get damaged in transit when fully assembled. For UK mainland customers, we offer three options:

COLLECTION: Collect from our Portland store and get a FREE air or 32% Nitrox fill.

SELF-ASSEMBLY: Isolator Bar and Twinning Bands are separated from the cylinders. (3 boxes)

FULLY ASSEMBLED: The set is sent fully assembled in one large and heavy box. Couriers find it hard to handle, and occasionally, sets get misaligned. If this happens, only the manifold needs to be replaced. We will arrange for a new manifold to be sent to you for you to assemble. The damaged manifold will be collected from you at our cost.

12L Eurocylinder Twinset specification

• O2 clean for 15 months from the date of purchase
• Working Pressure: 232 bar
• Cylinder diameter: 171mm
• Cylinder length without valve: 69cm
• Average cylinder weight without valve: 14.9kg
• Barrel type BtS Manifold (M25)
• Marine grade stainless steel BtS Bands

Ordering from outside of the UK mainland?

Due to shipping costs, Twinsets do not qualify for our standard shipping fees. If you want these delivered outside the UK mainland, contact us using our ONLINE CONTACT FORM with your delivery address. We will then be able to provide you with a non-binding shipping quote.

New to manifolds and twinsets? FAQ: See how it works

When the manifold centre valve is in the open position, both cylinders will be equalised, acting as a larger gas supply whether the diver is breathing off the primary or backup regulator.

As long as the left and right-hand valves remain open, each regulator will provide access to what is now a single gas supply.

When the manifold valve is in the closed position, the cylinders will be isolated from one another and run independently, effectively creating two separate gas supplies accessed respectively by the backup or primary regulator.

The main advantage of the twinset manifold is that it provides redundancy in case of failure involving either side. Closing the manifold valve will effectively isolate one cylinder (one side) from the other, providing the diver with the remaining gas from thevalve on the functioning side.

If the manifold is in an open position but either the left or right-hand cylinder valve is closed, the regulator connected to that valve (post) will not allow access to the gas in any of the cylinders.

That post’s valve will have shut down gas flow to the regulator attached to it, even if the manifold valve itself is open. However, theregulator on the open post will still have access to the total gas supply (both cylinders) unless the manifold is closed.